Rotation control system for a steering wheel and method

ABSTRACT

An autonomously driven vehicle is provided. The vehicle includes an autonomous driver assist system configured to provide directional control of a vehicle during an autonomous vehicle driving condition. The vehicle also includes a steering wheel. The vehicle further includes a plurality of road wheels electrically coupled to the steering wheel and controlled by the autonomous driver assist system in the autonomous vehicle driving condition and controlled by the steering wheel in a non-autonomous vehicle driving condition.

BACKGROUND OF THE INVENTION

The embodiments described herein relate to steering wheel assembliesand, more particularly, to a rotation control system for a steeringwheel.

As autonomously driven vehicles are developed, a number of opportunitieswill evolve related to entertainment and functionality for drivers.Steering wheels are commonly limited to standard driving positions dueto the need for a driver to handle the steering wheel during operationof the vehicle. These limitations may be unnecessary during anautonomous driving mode of a vehicle.

SUMMARY OF THE INVENTION

According to one aspect of the disclosure, a rotational control systemfor a steering wheel is provided. The rotational control system includesa steering wheel switchable between a rotational condition and anon-rotational condition. The rotational control system also includes asteering gear operatively coupled to a plurality of road wheels of avehicle, the steering wheel and the steering gear electrically coupledto each other. The rotational control system further includes acontroller in operative communication with the steering wheel and thesteering gear, the controller configured to control the steering gearindependent of the steering wheel when the vehicle is in an autonomousvehicle driving condition.

According to another aspect of the disclosure, an autonomously drivenvehicle is provided. The vehicle includes an autonomous driver assistsystem configured to provide directional control of a vehicle during anautonomous vehicle driving condition. The vehicle also includes asteering wheel. The vehicle further includes a plurality of road wheelselectrically coupled to the steering wheel and controlled by theautonomous driver assist system in the autonomous vehicle drivingcondition and controlled by the steering wheel when the vehicle is in anon-autonomous vehicle driving condition.

According to yet another aspect of the disclosure, a method ofcontrolling a rotational condition of a steering wheel is provided. Themethod includes switching between an autonomous vehicle drivingcondition and a non-autonomous vehicle driving condition, wherein aplurality of road wheels are electrically controlled by a steering wheelin the non-autonomous vehicle driving condition and the plurality ofroad wheels are controlled by an autonomous driving assist system in theautonomous vehicle driving condition. The method also includes switchingbetween a rotational condition and a non-rotational condition of thesteering wheel in the autonomous vehicle driving condition.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 schematically illustrates a vehicle having a rotational controlsystem for a steering wheel; and

FIG. 2 is a flow diagram illustrating a method of operation of therotational control system.

DETAILED DESCRIPTION

Referring now to FIG. 1, where the invention will be described withreference to specific embodiments, without limiting same, a rotationcontrol system 10 for a steering wheel 12 is provided. The rotationalcontrol system 10 facilitates switching between a rotatable condition ofthe steering wheel 12 and a non-rotatable condition of the steeringwheel 12. Such control is advantageous in a vehicle that is capable ofoperating in an autonomous driving mode. Autonomous driving refers tovehicles that are configured to perform operations without continuousinput from a driver (e.g., steering, accelerating, braking etc.) and maybe equipped with an Advanced Driver Assist System(s), also referred toherein as an autonomous driving assist system 15. The autonomous drivingassist system 15 includes processing equipment and a controller 26 thatallows the vehicle to be autonomously controlled using sensing,steering, and/or braking technology. When the autonomous driving assistsystem 15 is activated, the steering wheel 12 is not required forvehicle control and, therefore, rotation of the steering wheel is notrequired during the autonomous driving mode. Fixing the steering wheel12 in a non-rotational condition provides opportunities for a driver touse the steering wheel 12 as a workspace or armrest, for example, uponmovement of the steering wheel 12 to different orientations from astandard driving position. In some embodiments, the steering wheel 12 ismoved to a substantially horizontal orientation to allow objects to berested thereon. Furthermore, non-rotation of the steering wheel 12provides the ability to retract the steering wheel 12 to a stowedposition that allows a driver to enjoy additional legroom, and morespace generally.

The embodiments of the rotational control system 10 described herein maybe employed in conjunction with numerous types of vehicles. In someembodiments, the vehicle is referred to as a “drive-by-wire” automobilethat does not include a mechanical connection between the steering wheeland a steering gear 18 which is operatively coupled to a plurality ofroad wheels 20. In a drive-by-wire automobile, the steering wheel 12 andthe steering gear 18 are electrically coupled. Guidance of the vehicleis performed by the use of an electric power steering gear 18 with aninput shaft that is rotated by a first actuator 22, such as a servoactuator. The first actuator 22 receives an electronic communicationsignal of the steering wheel rotation made by the driver. The driver'sfeel of the road is simulated by a second actuator 24, such as a servoactuator, by applying tactile feedback in the form of torque to thesteering wheel 12. The second actuator 24 is operatively coupled to thesteering wheel 12. In the illustrated embodiment, the second actuator 24is coupled to a steering column 28 that is coupled to the steering wheel12.

As described above, the autonomous driving assist system 15 isconfigured to be activated when the autonomous vehicle driving conditionis desired. The driver is able to switch between the autonomous vehicledriving condition and a non-autonomous vehicle driving condition. Thenon-autonomous vehicle driving condition includes a driver controllingthe steering wheel to directionally control the vehicle in aconventional manner. The driver may switch between the autonomous andnon-autonomous driving conditions (i.e., activate and deactivate theautonomous driving mode) by a prompt (e.g., “handshake”), such as aspecific driver applied rotation or torque of the steering wheel 12.Alternative prompts may be used with a switch, button, handle, voiceprompt, etc. Regardless of the prompt, the driving mode is switched tothe desired condition.

Upon switching from the non-autonomous driving condition to theautonomous driving condition, the signal from the steering wheel 12 tothe steering gear 18 is halted or ignored, thereby deactivatingdirectional control of the road wheels 20 by the steering wheel. In sucha transition, the autonomous driving assist system 15 is activated todirectionally control the road wheels 20 of the vehicle. Sensors,navigational equipment, processing equipment, the controller 26 and/orother devices collectively are referred to as the autonomous drivingassist system 15. The controller 26 is shown independently forillustrative purposes, but it is to be appreciated that the controller26 is part of the autonomous driving assist system 15. In conjunctionwith the other devices of the autonomous driving assist system 15, thecontroller 26 directionally controls the road wheels 20 in theautonomous vehicle driving condition. In some embodiments, controlincludes controlling the first actuator 22, which works with thesteering gear 18 to control the road wheels 20.

While in the autonomous vehicle driving condition, the steering wheel isswitchable between the rotational condition and the non-rotationalcondition described above. In some cases, for a variety of reasons adriver may wish to maintain rotation of the steering wheel 12, evenwhile the vehicle is operated in the autonomous driving condition. Ifrotation is desired, the driver simply allows the steering wheel 12 torotate in a manner that corresponds to the angular displacement of theroad wheels 20 while keeping his or her hands off of the wheel, so as tonot inadvertently deactivate the autonomous driving condition. However,in many cases, a driver will desire a non-rotational condition of thesteering wheel 12. As described above, during the non-rotationalcondition the steering wheel 12 may be employed as a functional orentertainment related structure. For example, the steering wheel 12 maybe tilted to a substantially horizontal position, or any other angle,while the vehicle is in an autonomous driving condition. This enablesfor non-steering uses of the steering wheel 12. In one embodiment,non-rotation allows the steering wheel 12 to be used as a tray table torest arms or objects on. For example, a cell phone or laptop may beplaced thereon for use during the autonomous driving mode. In anotherembodiment, forward retraction of the steering wheel 12 toward theinstrument panel of the vehicle enlarges the cabin space for additionaldriver comfort and convenience. In yet another embodiment, thenon-rotating steering wheel provides a platform for electronic devicesmonitoring the cabin, driver, and vehicle controls due to the stationaryorientation of the steering wheel.

As is the case with switching between the autonomous and non-autonomousdriving conditions, the rotational and non-rotational conditions of thesteering wheel 12 may be switched by a prompt (e.g., “handshake”), suchas a specific driver applied rotation or torque of the steering wheel12. Alternative prompts may be used with a switch, button, handle, voiceprompt, etc.

Upon entering the autonomous driving condition, the autonomous drivingassist system 15 interrupts or discontinues the signal that is normallysent from the steering wheel input to the first actuator 22 and/orsteering gear 18, as described above. Simultaneously, the autonomousdriving assist system 15, via the controller 26, communicates with theoverall steering wheel assembly to stop rotation of the steering wheel12 upon entry into the non-rotational condition, thereby rotationallylocking the steering wheel 12. As described above, the driver ispermitted to selectively switch between the rotational condition and thenon-rotational condition while the vehicle is operated in the autonomousdriving condition to obtain the advantages described above.

As one skilled in the art can appreciate, the physical angular positionof the steering wheel 12 may be offset from the actual physical positionof the road wheels 20 during, and immediately subsequent to, operationof the vehicle in the autonomous driving condition. As such, uponswitching from the autonomous driving condition to the non-autonomousdriving condition, actual transfer of directional control of the roadwheels 20 to the driver is slightly delayed to accommodate realignmentof the steering wheel 12, and any associated components, with theposition of the road wheels 20. This delay is likely imperceptible tothe driver.

Referring to FIG. 2, a method of controlling rotation of the steeringwheel is illustrated in the form of a flow diagram. The method includesoperating 30 the vehicle in a drive-by-wire mode, with the driverdirectionally controlling 32 the road wheels with the steering wheel.The method also includes determining 34 if the autonomous driving assistsystem is activated. If it is not activated, the driver continues toprovide steering control of the vehicle 36. If activated, the autonomousdriving assist system provides steering control 38. In an activatedstate, the driver's selected wheel rotation condition is determined 40.If the driver has entered a prompt that selects the non-rotationalcondition of the steering wheel, the steering wheel enters thenon-rotational condition 42 and the steering wheel may be employed fornon-steering uses 44. If the driver has not entered a prompt thatselects the non-rotational condition, the driver simply keeps his or herhands off of the steering wheel 46 and the second actuator matches thetire angle to the steering wheel rotation 48.

As described above, the physical angular position of the steering wheel12 is matched to the actual physical position of the road wheels 20 uponswitching from the autonomous driving mode to the non-autonomous drivingmode. As shown in FIG. 2, the steering wheel is in a “straight ahead”position during the autonomous driving mode 50 in some embodiments. Adetermination 52 is made regarding whether the autonomous driving assistsystem is active. If active, no action is required 54 with respect toaligning the steering wheel to the road wheels. If not active 56, thesystem matches the steering wheel and road wheel angles 58 and thentransitions to allowing the driver to provide directional control of thevehicle 60.

The flow diagram of FIG. 2 and its associated description above relatesto a transition between the non-autonomous driving condition to theautonomous driving condition. As described above, to switch back to thenon-autonomous driving condition from the autonomous driving condition,the driver simply enters a specified prompt that deactivates control ofthe road wheels with the autonomous driving assist system.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description.

1. A rotational control system for a steering wheel comprising: asteering wheel switchable between a rotational condition and anon-rotational condition; a steering gear operatively coupled to aplurality of road wheels of a vehicle, the steering wheel and thesteering gear electrically coupled to each other; and a controller inoperative communication with the steering wheel and the steering gear,the controller configured to control the steering gear independent ofthe steering wheel when the vehicle is in an autonomous vehicle drivingcondition, the steering wheel retractable to a stowed position duringthe autonomous vehicle driving condition.
 2. The rotational controlsystem of claim 1, wherein the steering wheel is switchable between therotational condition and the non-rotational condition during theautonomous vehicle driving condition.
 3. The rotational control systemof claim 1, wherein the controller is part of an autonomous drivingassist system capable of determining and controlling directional controlof the vehicle.
 4. The rotational control system of claim 3, furthercomprising a first actuator operatively coupled to the steering gear,the first actuator controlled by the steering wheel in a non-autonomousvehicle driving condition, the first actuator controlled by theautonomous driving assist system in the autonomous vehicle drivingcondition.
 5. The rotational control system of claim 4, furthercomprising a second actuator operatively coupled to the steering wheel,the second actuator providing tactile feedback to a driver in responseto movement of the steering gear and the plurality of road wheels. 6.The rotational control system of claim 1, wherein a driver manuallyswitches between the autonomous vehicle driving condition and thenon-autonomous vehicle driving condition.
 7. The rotational controlsystem of claim 1, wherein a driver manually switches between therotational condition and the non-rotational condition while the vehicleis in the autonomous vehicle driving condition.
 8. (canceled)
 9. Therotational control system of claim 1, wherein the steering wheel isdisplaceable to a horizontal position during the autonomous vehicledriving condition.
 10. An autonomously driven vehicle comprising: anautonomous driver assist system configured to provide directionalcontrol of a vehicle during an autonomous vehicle driving condition; asteering wheel; and a plurality of road wheels electrically coupled tothe steering wheel and controlled by the autonomous driver assist systemin the autonomous vehicle driving condition and controlled by thesteering wheel when the vehicle is in a non-autonomous vehicle drivingcondition, the steering wheel retractable to a stowed position duringthe autonomous vehicle driving condition.
 11. The autonomously drivenvehicle of claim 10, wherein the steering wheel is switchable between arotational condition and a non-rotational condition.
 12. Theautonomously driven vehicle of claim 10, wherein the steering wheel isswitchable between the rotational condition and the non-rotationalcondition during the autonomous vehicle driving condition.
 13. Theautonomously driven vehicle of claim 10, further comprising a firstactuator operatively coupled to the plurality of road wheels and asecond actuator operatively coupled to the steering wheel, the secondactuator providing tactile feedback to a driver in response to movementof the plurality of road wheels.
 14. The autonomously driven vehicle ofclaim 10, wherein a driver manually switches between the autonomousvehicle driving condition and the non-autonomous vehicle drivingcondition.
 15. The autonomously driven vehicle of claim 10, wherein adriver manually switches between the rotational condition and thenon-rotational condition while the vehicle is in the autonomous vehicledriving condition.
 16. A method of controlling a rotational condition ofa steering wheel comprising: switching between an autonomous vehicledriving condition and a non-autonomous vehicle driving condition,wherein a plurality of road wheels are electrically controlled by asteering wheel in the non-autonomous vehicle driving condition and theplurality of road wheels are controlled by an autonomous driving assistsystem in the autonomous vehicle driving condition; switching between arotational condition and a non-rotational condition of the steeringwheel in the autonomous vehicle driving condition; and retracting thesteering wheel to a stowed position during the autonomous vehicledriving condition.
 17. (canceled)
 18. The method of claim 16, furthercomprising displacing the steering wheel to a horizontal position duringthe autonomous vehicle driving condition.
 19. The method of claim 16,further comprising determining when the rotational condition is to beactive and transitioning a steering wheel angle to match a road wheelangle.